Conventional guns and projectile launching weapon systems utilize the burning of chemical propellants to achieve high projectile velocity. In recent years there has been a renewed interest in projectile launchers which utilize electromagnetic energy. Generally speaking, electromagnetic launchers promise higher projectile velocities than launchers utilizing chemical propellants. Typical electromagnetic launchers utilize electromagnetic forces on conductive projectiles to accelerate the projectiles at high velocities toward a chosen target. A typical projectile frequently used with an electromagnetic launcher, unlike a conventional artillery round or small-arms bullet, does not require a primer and propellant or explosive. The absence of primers and chemical propellants makes electromagnetic projectiles safer to transport and store.
Applicant's co-pending application, titled "Electromagnetic Injector/Railgun," Ser. No. 910,915, Filed Sept. 22, 1986, now abandoned, discloses a novel railgun device in which a projectile is launched in a direction perpendicular to two parallel conducting rails. The projectile is launched by the repulsive force created by oppositely-flowing currents through the two rails. One of the rails is completely severed by a gap, dimensioned to receive the projectile. If the projectile is not within the gap, current cannot flow through the rails. However, when the projectile is injected into the gap (by mechanical or pneumatic means) the projectile spans the gap, and current flows through the rails and through the projectile, generating the aforementioned repulsive force and ejecting the projectile from the gap towards a target.
To generate a large repulsive force (and thus achieve high projectile velocities) it is necessary that high currents must flow through the rails and the projectile. Experiments have shown that slight mismatches at the interface between the projectile and the sides of the gap cause arcing and rail damage. Damage to the rail makes the firing of subsequent shots difficult, if not impossible and requires time-consuming maintenance.
Those concerned with railgun development have consistently sought new devices for eliminating arcing and rail damage.